As the process of turning hard water into soft water involves chemicals, there is naturally a concern for the environment and the possible damage this causes to the surrounding ecosystem. In any case, an artificial chemical process is the human method of controlling a set of components into a specified form for a number of practical reasons. Typically, chemicals are used to enhance the original form of the substance with the aim of improving the quality of the end product, e.g. bleaches for cleaning, preventing damage to humans and removing threats. In the instance of softened water, the process is to prevent hard water damaging expensive and valuable appliances installed in the home.
To explore this issue further, the difference between hard and soft water must be understood to identify if softened water has a detrimental effect on the environment, and, most importantly, is it beneficial for us to drink and use in daily life?
Hard water v soft water
The terms ‘hard water’ and ‘soft water’ are both common terms used in everyday life, but what exactly is the difference between the two? Hard water is typically defined by possessing a high level of dissolved mineral content, specifically calcium (Ca) and magnesium (Mg). This is the result of a natural process as water transports through soil and rock, dissolving small amounts of minerals and suspends them in solution. Calcium and magnesium are the most common minerals that result in water becoming ’hard’ and the level of hardness becomes greater as the mineral content increases.
‘Hard water’ is simple to distinguish as it does not produce lather when in contact with soap, shampoo or washing liquids. The implication of this is the inability to wash properly, whether that may be washing the skin or kitchenware. At high temperatures, the magnesium and calcium react, producing a hard slimy white substance commonly known as ‘lime scale’. This is particularly bad for domestic appliances, such as kettles and boiler elements and can cause huge problems in industrial settings. The direct result of this build-up in limescale is that everyday appliances become less energy-efficient, costing the owner financially. British Water state that even 1.6mm of scale in heating systems causes a 12% loss in heat transfer from the energy source to water. This causes the heaters and boilers to run longer and hotter, using more gas or electricity, resulting in a higher running cost. However, because hard water is full of minerals, it is often sought after for its unique properties and health benefits e.g. mineral-rich springs such as those in Bath, England are internationally renowned.
‘Soft water’ is regarded as treated water as it is free of the mentioned minerals, making household chores easier and lower energy bills. Through the use of a water softener, it’s possible to change the properties of hard water into soft water. The hard water passes through a tank containing resin beads holding ‘soft’ sodium ions. The ‘hard’ calcium and magnesium ions are exchanged for sodium ions, thus softening the water, with the sodium or potassium ions passing down through the resin bed and out the softener’s drain.
The impacts on the environment and humans
The most common concern for the environment when using a water softener is the discharge of salt brine into the wastewater collection system. This by-product of the water softener can ultimately have a negative impact on recycled water and wastewater discharge. However there is a strong argument that this by-product can easily be drained into a separate tank and treated.
Another concern is the increase in sodium content. Although this is great for producing soft, kind to the skin goods such as bath robes, lather from soap and reduced risk of damage to appliances, there are some other areas of contention. These can range from the use of soft water in fish ponds and aquariums, and whether or not it is safe for pets to drink such fluids.
It is commonly discussed that soft water is beneficial in treating skin conditions such as eczema, and there are a wealth of studies conducted by well-respected bodies such as the National Eczema Society which support this theory. It is difficult to state whether that this is due to the type of water and the overall benefits on the skin.
To conclude, the overall impact of softened water on the environment is not detrimental, particularly as the use of a separate tank to collect the salt brine removes any possibility of treated water having a harmful effect on the local environment. Furthermore, this reduces the likelihood of transporting treated water any further and therefore impacting on the local ecosystem. Humans realise the benefits of softened water due to the reduction of lime scale and the impact this can have on the efficiency of domestic appliances and reduced running costs.
About the author: Mike Sutton has become increasingly interested in realising the benefits of water softeners through EcoWater and understanding the impacts on the environment.
Photo: Mike Sutton